That'll do it =-)
The nightlies actually use a new dll fairly recently too, as there was an upgrade in the wxWidgets framework from version 2.6.3 to 2.8.4. Could also be expecting another upgrade to 2.8.6 if it proves stable enough over the next month or two (recent set of bug fixes applied over x.5 widgets release).
So keep an eye on the sticky topics at the top of the nightlies page. It gets updated anytime that a new dll is required, and each nightly release always has a link to whatever the current dll happens to be.